Optical recording materials having high storage density

ABSTRACT

The invention relates to an optical recording medium comprising a substrate, a reflecting layer and a recording layer based on compounds of formula (I) wherein G 1  and G 2  are each independently of the other, A 1  and A 2  are each independently of the other N(R 12 ), O, S or Se and A 3  is C(C 1 -C 5 alkyI) 2 , C(C 4 -C 5  alkylene), N(R 12 ), O, S, Se, N═C(R 13 ) or unsubstituted or R 14 -substituted CH═CH; M 1  is a transition metal of groups (IX) to (XIII), preferably Co, Cu, Ni, Pd or Zn, especially Co, Cu or Ni; Q 1  and Q 2  are each independently of the other C(R 15 ), N or P, . . . For the detailed definitions of the further substituents, see the description. Recording and playback are effected especially at a wavelength of from 350 to 500 nm, for example using a blue laser. The recording and playback quality is excellent and allows a high storage density. Also claimed are new compounds of formula (I), with the exception of the compounds disclosed in J. Org. Chem. 67/16, 5753-5772 [2002].

The invention relates to new optical recording materials that haveexcellent recording and playback quality especially at a wavelength of350-500 nm. Recording and playback can be effected very advantageouslywith high sensitivity at the same wavelength, and the storage densitythat is achievable is significantly higher than in the case of knownmaterials. In addition, the materials according to the invention havevery good storage properties before and after recording, even underespecially harsh conditions, such as exposure to sunlight or fluorescentlighting, heat and/or high humidity. In addition, their manufacture issimple and readily reproducible using customary coating processes, suchas spin-coating.

WO 02/082438 discloses the use of ionic salts, including those withmetal complex anions, for optical recording materials. Those colorantsare always substituted by alkyl, alkenyl, aryl or heteroaryl at thenitrogen atom. Their optical properties do not, however, fully satisfyincreased demands. In particular, the refractive index as well as theabsorption and the steepness of the absorption band on its longwavelength flank in the solid still leave something to be desired.

JP-A-11/34500, JP-A-11/92479 and EP-A-0 903 733 disclose metal and boroncomplexes of colorants of formulae

which can be used at from 520 to 690 nm for optical recording materialssuch as CD-R or DVD-RF Here too, however, the optical properties,especially the spectral properties in or near the UV range that arenecessary for the highest possible storage densities, and theinformation density per unit surface area are not able to satisfy thehighest demands as desired. The information density per unit surfacearea is far lower than is desirable.

Conventional optical recording materials therefore satisfy high demandsonly to some extent, or do not satisfy all demands to an entirelysatisfactory degree at the same time.

On the other hand, J. Org. Chem. 67/16, 5753-5772 [2002] describes thesynthesis of a number of bis(o-azaheteroaryl)methanes and theircoordination properties with respect to divalent transition metals,heteroaryl being 1,3-azol-2-yl, 1,3-benzazol-2-yl and azinyl and thetransition metals being Zn, Cu, Co, Ni, Hg and Pd. Inter alia 2:1 saltcomplexes of bis(benzothiazol-2-yl)methane andbis(benzoxazol-2-yl)methane with copper(II) chloride and nickel(II)sulfate, and cobalt(II) chloride and palladium(II) nitrate aredisclosed, whereas bis(thiazol-2-yl)methane yields, with deprotonation,neutral 2:1 chelates with Zn(II), Cu(II), Ni(II) and Co(II). Allsubstances are strongly coloured.

The aim of the invention is an optical recording medium having highinformation density, sensitivity and data reliability. Such a recordingmedium should be robust, durable and easy to use. Furthermore, it shouldbe inexpensive to manufacture as a mass-produced product and shouldrequire equipment that is as small and inexpensive as possible.

The invention therefore relates to an optical recording mediumcomprising a substrate, a recording layer and optionally one or morereflecting layers, wherein the recording layer comprises a compound offormula

or a tautomer thereof, wherein

G₁ and G₂ are each independently of the other

A₁ and A₂ are each independently of the other N(R₁₂), O, S or Se and A₃is C(C₁-C₅alkyl)₂, C(C₄-C₅alkylene), N(R₁₂), O, S, Se, N═C(R₁₃) orunsubstituted or R₁₄-substituted CH═CH;

M₁ is a transition metal of groups IX to XII, preferably Co, Cu, Ni, Pdor Zn, especially Co, Cu or Ni;

Q₁ and Q₂ are each independently of the other C(R₁₅), N or P;

R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈ and R₁₄ are each independently of theothers hydrogen, R₁₈, or C₆-C₁₂aryl, C₄-C₁₂heteroaryl, C₇-C₁₂aralkyl orC₅-C₁₂heteroaralkyl each unsubstituted or substituted by one or more,where applicable identical or different, radicals R₁₈; or

R₁ and R₂, R₃ and R₄, R₅ and R₆, R₅ and R₁₃ and/or R₅ and R₁₄, togetherin pairs, are C₃-C₆alkylene or C₃-C₆alkenylene, each of which isunsubstituted or substituted by one or more, where applicable identicalor different, radicals R₁₇ and may be uninterrupted or interrupted by O,S or N(R₁₂), or 1,4-buta-1,3-dienylene,

each of which is unsubstituted or substituted by one or more, whereapplicable identical or different, radicals R₁₈ and in which 1 or 2carbon atoms may have been replaced by nitrogen;

R₉, R₁₂ and R₁₃ are each independently of the others C₁-C₂₄alkyl,C₃-C₂₄cycloalkyl, C₂-C₂₄alkenyl, C₃-C₂₄cycloalkenyl,C₁-C₄alkyl[O—C₁-C₄alkylene]_(m) or C₁-C₄alkyl-[NH—C₁-C₄alkylene]_(m),each of which is unsubstituted or substituted by one or more, whereapplicable identical or different, radicals R₁₇; or C₆-C₁₂aryl,C₄-C₁₂heteroaryl, C₇-C₁₂aralkyl or C₅-C₁₂heteroaralkyl, each of which isunsubstituted or substituted by one or more, where applicable identicalor different, radicals R₁₈;

R₁₀, R₁₁ and R₁₈ are each independently of the others halogen, nitro,cyano, thiocyanato, hydroxy, O—R₁₉, O—CO—R₁₉, S—R₁₉, CHO, COR₂₀,CHOR₁₉OR₂₃, CR₂₀OR₁₉OR₂₃, R₁₈, N═N—R₁₆ , N═CR₁₉R₂₀, N═CR₂₁R₂₂,C(R₁₅═NR₁₉, C(R₁₅)═NR₂₁, C(R₁₅)═CR₂₁R₂₂, NH₂, NH—R₁₉, NR₁₉R₂₀, NH₃ ⁺,NH₂R₁₉ ⁺, NHR₁₉R₂₀ ⁺, NR₁₉R₂₀R₂₃ ⁺, CONH₂, CONHR₁₉, CONR₁₉R₂₀, SO₂R₁₉,SO₂NH₂, SO₂NHR₁₉, SO₂NR₁₉R₂₀, COOH, COOR₁₉, OCOOR₁₉, NHCOR₁₉, NR₁₉COR₂₃,NHCOOR₁₉, NR₁₉COOR₂₃, ureido, NR₁₉—CO—NHR₂₃, B(OH)₂, B(OH)(OR₁₉),B(OR₁₉)OR₂₃, phosphato, PR₁₉R₂₃, POR₁₉OR₂₃, P(═O)OR₁₉OR₂₃, OPR₁₉R₂₃,OPR₁₉OR₂₃, OP(═O)R₁₉OR₂₃, OP(═O)OR₁₉OR₂₃, OPO₃R₁₉, sulfato, sulfo, orC₁-C₁₂alkyl, C₃-C₁₂cycloalkyl, C₁-C₁₂alkylthio, C₃-C₁₂cycloalkylthio,C₁-C₁₂alkoxy or C₃-C₁₂cycloalkoxy each unsubstituted or substituted byone or more, where applicable identical or different, radicals R₁₇;

R₁₅ is hydrogen, cyano, hydroxy, C₁-C₁₂alkoxy, C₃-C₁₂cycloalkoxy,C₁-C₁₂alkylthio, C₃-C₁₂cycloalkylthio, amino, NHR₂₄, NR₂₅R₂₆, R₂₇,halogen, nitro, formyl, N═N—R₂₇, C(R₁₄)═CR₂₁R₂₂, C(R₁₄)═NR₁₉, COO—R₂₅,carboxy, carbamoyl, CONH—R₂₅, CONR₂₅R₂₆, N═CR₁₉R₂₀, or C₁-C₁₂alkyl,C₃-C₁₂cycloalkyl, C₂-C₁₂alkenyl or C₃-C₁₂cycloalkenyl each unsubstitutedor substituted by one or more, where applicable identical or different,halogen, hydroxy, C₁-C₁₂alkoxy or C₃-C₁₂cycloalkoxy radicals;

R₁₆ is C₆-C₁₂aryl, C₄-C₁₂heteroaryl, C₇-C₁₂aralkyl orC₅-C₁₂heteroaralkyl, each of which is unsubstituted or substituted byone or more, where applicable identical or different, radicals R₂₈;

R₁₇ is halogen, hydroxy, O—R₂₅, O—CO—R₂₅, S—R₂₅, NH₂, NH—R₂₅, NR₂₅R₂₆,NH₃ ⁺, NH₂R₂₅ ⁺, NHR₂₅R₂₆ ⁺, NR₂₄R₂₅R₂₆ ⁺, NR₂₅—CO—R₂₄, NR₂₅COOR₂₄,cyano, formyl, COO—R₂₅, carboxy, carbamoyl, CONH—R₂₅, CONR₂₅R₂₆, ureido,NH—CO—NHR₂₄, NR₂₅—CO—NHR₂₄, phosphato, PR₂₅R₂₄, POR₂₅OR₂₄,P(═O)OR₂₅OR₂₄, OPR₂₅R₂₄, OPR₂₅OR₂₄, OP(═O)R₂₅OR₂₄, OPO₃R₂₅,OP(═O)OR₂₅OR₂₄, SO₂R₂₅, sulfato, sulfo, R₂₇, N═N—R₂₇, or C₁-C₁₂alkoxy orC₁-C₁₂cycloalkoxy each unsubstituted or mono- or poly-substituted byhalogen;

R₁₉, R₂₀ and R₂₃ are each independently of the others R₁₆, orC₁-C₁₂alkyl, C₃-C₁₂cycloalkyl, C₂-C₁₂alkenyl or C₃-C₁₂cycloalkenyl eachunsubstituted or substituted by one or more, where applicable identicalor different, halogen, hydroxy, C₁-C₁₂alkoxy or C₃-C₁₂cycloalkoxyradicals; or

R₁₄ and R₁₉ together, R₁₅ and R₁₉ together and/or R₁₉ and R₂₃ togetherare C₂-C₁₂alkylene, C₃-C₁₂cycloalkylene, C₂-C₁₂alkenylene orC₃-C₁₂cycloalkenylene, each of which is unsubstituted or substituted byone or more, where applicable identical or different, halogen, hydroxy,C₁-C₁₂alkoxy or C₃-C₁₂cycloalkoxy radicals; or

R₁₉ and R₂₀ together with the common nitrogen are pyrrolidine,piperidine, piperazine or morpholine, each of which is unsubstituted ormono- to tetra-substituted by C₁-C₄alkyl; or carbazole, phenoxazine orphenothiazine, each of which is unsubstituted or substituted by one ormore, where applicable identical or different, radicals R₂₆;

R₂₁ and R₂₂ are each independently of the other NR₂₅R₂₆, CN, CONH₂,CONHR₁₉, CONR₁₉R₂₀ or COOR₂₀;

R₂₄, R₂₅ and R₂₆ are each independently of the others C₁-C₁₂alkyl,C₃-C₁₂cycloalkyl, C₂-C₁₂alkenyl, C₃-C₁₂cycloalkenyl, C₆-C₁₂aryl,C₄-C₁₂heteroaryl, C₇-C₁₂aralkyl or C₅-C₁₂heteroaralkyl; or

R₂₅ and R₂₈ together with the common nitrogen are pyrrolidine,piperidine, piperazine or morpholine, each of which is unsubstituted ormono- to tetra-substituted by C₁-C₄alkyl;

R₂₇ is C₆-C₁₂aryl, C₄-C₁₂heteroaryl, C₇-C₁₂aralkyl orC₅-C₁₂heteroaralkyl, each of which is unsubstituted or substituted byone or more, where applicable identical or different, radicals R₁₈;

R₂₈ is nitro, SO₂NHR₂₅, SO₂NR₂₅R₂₆, or C₁-C₁₂alkyl, C₃-C₁₂cycloalkyl,C₁-C₁₂alkylthio, C₃-C₁₂cycloalkylthio, C₁-C₁₂alkoxy or C₃-C₁₂cycloalkoxyeach unsubstituted or substituted by one or more, where applicableidentical or different, radicals R₁₇; and

m is a number from 1 to 10.

When R₅ forms a bridge with R₆, R₅ may not at the same time form abridge with R₁₃ or R₁₄.

It will be understood that acidic groups, such as carboxy, sulfo,sulfato and phosphate, may also be in the form of a salt, for example analkali metal, alkaline earth metal, ammonium or phosphonium salt, suchas Li⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺, Cu²⁺, Ni²⁺, Fe²⁺, Co²⁺, Zn²⁺, Sn²⁺, La³⁺,ammonium, methylammonium, ethylammonium, isopropylammonium, ™Primene81-R, ™Rosin Amine D, pentadecylammonium, ™Primene JM-T,dicyclohexylammonium, tetramethylammonium, tetraethylammonium,tetrabutylammonium, benzyltrimethylammonium, benzyltriethylammonium,methyltrioctylammonium, tridodecylmethylammonium, tetrabutylphosphonium,tetraphenylphosphonium, butyltriphenylphosphonium orethyltriphenylphosphonium, or any of the cations B-1 to B-169 mentionedin U.S. Pat. No. 6,225,024, to which individually reference is expresslymade here.

Halogen is chlorine, bromine, fluorine or iodine, preferably fluorine orchlorine, especially fluorine on alkyl (for example trifluoromethyl,α,α,α-btrifluoroethyl or perfluorinated alkyl groups, such asheptafluoropropyl) and chlorine on aryl, heteroaryl or on the arylmoiety of aralkyl or on the heteroaryl moiety of heteroaralkyl.

Alkyl, cycloalkyl, alkenyl or cycloalkenyl can be straight-chain orbranched, or monocyclic or polycyclic. Alkyl is, for example, methyl,straight-chain C₂-C₂₄alkyl or preferably branched C₃-C₂₄alkyl. Alkenylis, for example, straight-chain C₂C₂₀alkenyl or preferably branchedC₃-C₂₄alkenyl. The invention therefore relates especially also tocompounds of formula (I) containing branched C₃-C₂₄alkyl or branchedC₃-C₂₄alkenyl, and also to optical recording materials comprising suchcompounds. C₁-C₂₄Alkyl is therefore, for example, methyl, ethyl,n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl,2-pentyl, 3-pentyl, 2,2-dimethylpropyl, n-hexyl, n-octyl,1,1,3,3-tetramethylbutyl, 2-ethylhexyl, nonyl, decyl, dodecyl,tetradecyl, hexadecyl, octadecyl, elcosyl, heneicosyl, docosyl ortetracosyl. C₃-C₂₄Cycloalkyl is, for example, cyclopropyl, cydobutyl,cyclopentyl, cyclohexyl, trimethylcyclohexyl, menthyl, thujyl, bornyl,1-adamantyl or 2-adamantyl.

C₂-C₂₀Alkenyl and C₃-C₂₀cycloalkenyl are C₂-C₂₀alkyl andC₃-C₂₀cycloalkyl that is mono- or poly-unsaturated, wherein two or moredouble bonds may be isolated or conjugated, for example vinyl, allyl,2-propen-2-yl, 2-buten-1-yl, 3-buten-1-yl, 1,3-butadien-2-yl,2-cyclobuten-1-yl, 2-penten-1-yl, 3-penten-2-yl, 2-methyl-1-buten-3-yl,2-methyl-3-buten-2-yl, 3-methyl-2-buten-1 -yl, 1,4pentadien-3-yl,2-cyclopenten-1-yl, 2-cyclohexen-1-yl, 3-cyclohexen-1-yl,2,4-cyohexadien-1-yl, 1-p-menthen-8-yl, 4(10)-thuien-10-yl,2-horbornen-1-yl, 2,5-norbornadien-1-yl, 7,7dimethyl-2,4-norcaradien-3ylor the various isomers of hexenyl, octenyl, nonenyl, decenyl, dodecenyl,tetradecenyl, hexadecenyl, octadecenyl, eicosenyl, henelcosenyl,docosenyl, tetracosenyl, hexadienyl, octadienyl, nonadienyl, decadienyl,dodecadienyl, tetradecadienyl, hexadecadienyl, octadecadienyl oreicosadienyl.

C₇-C₁₂Aalkyl is, for example, benzyl, 2-benzyl-2-propyl, β-phenyethyl,9-fluorenyl, α,α-dimethylbenzyl, ω-henyl-butyl or ω-phenyl-hexyl. WhenC₇-C₁₂aralkyl is substituted, both the alkyl moiety and the aryl moietyof the aralkyl group can be substituted, the latter alternative beingpreferred.

C₆-C₁₂Aryl is, for example, phenyl, naphthyl, biphenylyl or 2-fluorenyl.

C₄-C₁₂Heteroaryl is an unsaturated or aromatic radical having 4n+2conjugated π-electrons, for example 2-thienyl, 2-furyl, 2-pyridyl,2-thiazolyl, 2-oxazolyl, 2-imidazolyl, isothiazolyl, triazolyl or anyother ring system consisting of thiophene, furan, pyridine, thiazole,oxazole, imidazole, isothiazole, triazole, pyridine and benzene ringsand unsubstituted or substituted by from 1 to 6 ethyl, methyl, ethyleneand/or methylene substituents, for example benzotriazolyl, and in thecase of N-heterocycles where applicable also those in the form of theirN-oxides.

C₅-C₁₂Heteroaralkyl is, for example, C₁-C₈alkyl substituted byC₄-C₁₁heteroaryl.

Furthermore, aryl and aralkyl can also be aromatic groups bonded to ametal, for example in the form of metallocenes of transition metalsknown per se, more especially

The transition metal M₁ is preferably in the form of a doubly positivelycharged cation, for example Co²⁺, Cu²⁺, Ni²⁺, Pd²⁺ or Zn²⁺, especiallyCo²⁺, Cu²⁺ or Ni²⁺.

The compound of formula (I) may also be a cation which has beenneutralised with an inorganic, organic or organometallic anion, forexample when one or more ammonium groups are present or when thetransition metal has one or more excess positive charges, such as inCo³⁺. The inorganic, organic or organometallic anion may be, forexample, the anion of a mineral acid, of the conjugated base of anorganic acid (for example an alcoholate, phenolate, carboxylate,sulfonate or phosphonate) or an organometallic complex anion, forexample fluoride, chloride, bromide, iodide, perchlorate, periodate,nitrate, hydrogen carbonate, ½ carbonate, ½ sulfate, C₁-C₄alkyl sulfate,hydrogen sulfate, ⅓ phosphate, ½ hydrogen phosphate, dihydrogenphosphate, ½ C ₁-C₄alkanephosphonate,C₁-C₄alkane-C₁-C₁₂alkylphosphonate, di-C₁-C₄alkylphosphinate,tetrafluoroborate, hexafluorophosphate, hexafluoroantimonate, acetate,trifluoroacetate, heptafluorobutyrate, ½ oxalate, methanesulfbnate,trifluoromethanesulfonate, benzenesulfonate, tosylate,p-chlorobenzenesulfonate, p-nitrobenzenesulfonate, phenolate, benzoateor a negatively charged metal complex.

The person skilled in the art will readily recognise that it is alsopossible to use other anions with which he is familiar. It will beself-evident to him that $\frac{1}{x}$of an inorganic, organic or organometallic anion having x negativecharges, for example ½.SO₄ ²⁻, is a multiply charged anion whichneutralises several singly charged cations or a cation having x charges,as the case may be.

Phenolates or carboxylates are, for example, of formula

(wherein R₂₉, R₃₀ and R₃₁ are each independently of the others hydrogen,R₁₈, or C₆-C₁₂aryl, C₄-C₁₂heteroaryl, C₇-C₁₂aralkyl orC₅-C₁₂heteroarylalkyl each unsubstituted or substituted by one or more,where applicable identical or different, radicals R₁₈, for exampleanions of C₁-C₁₂alkylated, especially tert-C₄-C₈alkylated, phenols andbenzoic acids, such as

Preference is given to compounds of formula (I) wherein

A₁, A₂ and A₃ are each independently of the others O, S or N(R₁₂) and/orQ₁ and Q₂ are C(R₁₅) or N;

G₁ and G₂ are each independently of the other

R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈ and R₁₄ are each independently of theothers hydrogen, R₁₈, or C₆-C₁₂aryl or C₇-C₁₂aralkyl each unsubstitutedor substituted by one or more, where applicable identical or different,radicals R₁₈;

R₉, R₁₂ and R₁₃ are each independently of the others unsubstituted orR₁₇-substituted C₁-C₈alkyl;

R₁₀ and R₁₈ are each independently of the other halogen, nitro, cyano,O—R₁₉, formyl, CH═C(CN)₂, CH═C(CN)CONH₂, CH═C(CN)CONHR₁₉,CH═C(CN)CONR₁₉R₂₀, CH═C(CN)COOR₁₉, CH═C(COOR₁₉)COOR₂₀, CONH₂, CONHR₁₉,CONR₁₉R₂₀, SO₂C₁-C₁₂alkyl, SO₂NH₂, SO₂NHR₁₉, SO₂NR₁₉R₂₀, COOH, COOR₁₉,NHCOR₁₉, NR₁₉COR₂₃, NHCOOR₁₉, NR₁₉COOR₂₃, ureido, P(═O)OR₁₉OR₂₃, sulfo,or C₁-C₁₂alkyl, C₁-C₁₂alkylthio or C₁-C₁₂alkoxy each unsubstituted orsubstituted by one or more, where applicable identical or different,radicals R₁₇;

R₁₅ is hydrogen, cyano, halogen, nitro, formyl, N═N—R₂₇, C(R₁₄)═CR₂₁R₂₂,C(R₁₄)═NR₁₉, COO—R₂₅, carboxy, carbamoyl, CONH—R₂₅, CONR₂₅R₂₆, orC₁-C₁₂alkyl unsubstituted or substituted by one or more halogensubstituents;

R₁₆ is unsubstituted or substituted C₆-C₁₂aryl or C₇-C₁₂aralkyl,especially a metallocenyl radical;

R₁₇ is halogen, hydroxy, O—R₂₅, amino, NH—R₂₅, NR₂₅R₂₆, NR₂₅—CO—R₂₄,NR₂₅COOR₂₄, cyano, COO—R₂₅, carboxy, CONH—R₂₅, CONR₂₅R₂₆, sulfato,sulfo, or C₁-C₁₂alkoxy unsubstituted or mono- or poly-substituted byhalogen;

R₁₉, R₂₀ and R₂₃ are each independently of the others C₁-C₁₂alkylunsubstituted or substituted by one or more, where applicable identicalor different, halogen, hydroxy or C₁-C₁₂alkoxy radicals% orunsubstituted C₆-C₁₂aryl or C₇-C₁₂aralkyl; or

R₁₉ and R₂₀ together with the common nitrogen are morpholine, orpiperidine N-substituted by C₁-C₄alkyl;

R₂₅, R₂₆ and R₂₄ are each independently of the others C₁-C₁₂alkyl,C₂-C₁₂alkenyl, C₈-C₁₂aryl or C₇-C₁₂aralkyl; or

R₂₅ and R₂₆ together with the common nitrogen are morpholine, orpiperidine N-substituted by C₁-C₄alkyl; and/or

m is a number from 1 to 4.

Special preference is given to compounds of formula (I) wherein Q₁ andQ₂ are C(R₁₅); G₁ and G₂ are

and A₁, A₂ and A₃ are O, S or N(R₁₂);

R₁₂ is C₁-C₂₄allyl, C₁-C₄alkyl-[O—C₁-C₄alkylene]_(m) orC₁-C₄alkyl-[NH—C₁-C₄alkylene]_(m), each of which is unsubstituted orsubstituted by one or more, where applicable identical or different,radicals R₁₇, or C₆-C₁₂aryl unsubstituted or substituted by one or more,where applicable identical or different, radicals R₁₈;

R₁₅ is hydrogen, cyano, COO—R₂₅ or C₁-C₁₂alkyl;

R₁₇ is halogen, hydroxy, O—R₂₅, cyano, COO—R₂₅ or carboxy; and

R₁₈ is halogen, nitro, cyano, O—R₁₉, CH═C(CN)₂, COOR₁₉, ureido,CONR₂₅R₂₆, SO₂R₂₅, P(═O)OR₁₉OR₂₃ or unsubstituted or substitutedC₁-C₁₂alkyl.

Those preferred meanings apply both individually and in any combination.The compounds of formula (I) generally exhibit more advantageousproperties, the more preferred individual features they have.

Also preferred are compounds of formula (I) wherein

The recording layer advantageously comprises a compound of formula (I)or a mixture of such compounds as main component, for example at least30% by weight, preferably at least 60% by weight, especially at least80% by weight Further customary constituents are possible, for exampleother chromophores (for example those disclosed in WO 01/75873, orothers having an absorption maximum at from 300 to 1000 nm),stabilisers, ¹O₂—, triplet- or luminescence-quenchers, melting-pointreducers, decomposition accelerators or any other additives that havealready been described in optical recording media. Preferably,stabilisers or fluoresence-quenchers are added if desired.

When the recording layer comprises further chromophores, the amount ofsuch chromophores should preferably be small, so that the absorptionthereof at the wavelength of the inversion point of thelongest-wavelength flank of the absorption of the entire solid layer isa fraction of the absorption of the pure compound of formula (I) in theentire solid layer at the same wavelength, advantageously at most ⅓,preferably at most ⅕, especially at most 1/10. The absorption maximum ispreferably higher than 425 nm, especially higher than 500 nm.

Stabilisers, ¹O₂—, triplet- or luminescence-quenchers are, for example,metal complexes of N- or S-containing enolates, phenolates,bisphenolates, thiolates or bisthiolates or of azo, azomethine orformazan dyes, such as bis(4-dimethylamino-dithiobenzil)nickel [CASN^(o) 38465-55-3], ®Irgalan Bordeaux EL, ®Cibafast N or similarcompounds, hindered phenols and derivatives thereof (optionally also ascounter-ions X), such as ®Cibafast AO, o-hydroxyphenyl-triazoles or-triazines or other UV absorbers, such as ®Cibafast W or ®Cibafast P orhindered amines (TEMPO or HALS, also as nitroxides or NOR-HALS,optionally also as counter-ions X), and also as cations diummonium,Paraquat™ or Orthoquat™ salts, such as ®Kayasorb IRG 022, ®Kayasorb IRG040, optionally also as radical ions, such asN,N,N′,N′-tetrakis(4-dibutylaminophenyl)p-phenyleneamine-ammoniumhexafluorophosphate, hexafluoroantimonate or perchlorate. The latter areavailable from Organica (Wolfen/Del.); ®Kayasorb brands are availablefrom Nippon Kayaku Co. Ltd., and ®Irgalan and ®Cibafast brands areavailable from Ciba Spezialitätenchemie AG.

Many such structures are known, some of them also in connection withoptical recording media, for example from U.S. Pat. No. 5,219,707,JP-A-06/199045, JP-A-07/76169, JP-A-07/262604 or JP-A-2000/272241. Theymay be, for example, salts of the metal complex anions disclosed abovewith any desired cations, for example the cations disclosed above, ormetal complexes, illustrated, for example, by a compound of formula

The person skilled in the art will know from other optical informationmedia, or will easily identify, which additives in which concentrationare particularly well suited to which purpose. Suitable concentrationsof additives are, for example, from 0.001 to 1000% by weight preferablyfrom 1 to 50% by weight, based on the recording medium of formula (I).

The optical recording materials according to the invention exhibitexcellent spectral properties of the solid amorphous recording layer.The refractive index is extraordinarily high, in some cases even above2.5. By virtue of an aggregation tendency in the solid that issurprisingly low for such compounds, the absorption band is narrow andintense, the absorption band being especially steep on thelong-wavelength side. Crystallites are unexpectedly and veryadvantageously not formed or are formed only to a negligible extent Thereflectivity of the layers in the range of the writing and readingwavelength is very high in the unwritten state.

By virtue of those excellent layer properties it is possible to obtain arapid optical recording having high sensitivity, high reproducibilityand geometrically very precise mark boundaries, the refractive index andthe reflectivity changing substantially, which gives a high degree ofcontrast. The differences in the mark lengths and the interval distances(“jitter”) are very small, which enables a high storage density to beobtained using a relatively thin recording channel with a narrow trackspacing (“pitch”). In addition, the recorded data are played back withan astonishingly low error rate, so that error correction requires onlya small amount of storage space.

By virtue of the excellent solubility, including in apolar solvents,solutions can be used even in high concentrations without troublesomeprecipitation, for example during storage, so that problems duringspin-coating are largely eliminated. This applies especially tocompounds containing branched C₃-C₈alkyl.

Recording and playback can take place at the same wavelength, thereforeadvantageously requiring a simple optical system with a single lasersource of advantageously from 350 to 500 nm, preferably from 370 to 450nm. Especially preferred is the UV range from 370 to 390 nm, especiallyapproximately 380 nm, or especially at the edge of the visible range offrom 390 to 430 nm, more especially approximately 405±5 nm. In the fieldof compact, blue or violet laser diodes (such as Nichia GaN 405 nm) withan optical system of high numerical aperture the marks can be so smalland the tracks so narrow that up to about 20 to 25 Gb per recordinglayer is achievable on a 120 mm disc. At 380 nm it is possible to useindium-doped UV-VCSELs (Vertical-Cavity Surface-Emitting Laser), whichlaser source already exists as a prototype [Jung Han et al., see MRSInternet J. Nitride Semicond. Res. 5S1, W6.2 (2000)].

The invention therefore relates also to a method of recording or playingback data, wherein the data on an optical recording medium according tothe invention are recorded or played back at a wavelength of from 350 to500 nm.

The recording medium is based on the structure of known recording mediaand is, for example, analogous to those mentioned above. It may becomposed, for example, of a transparent substrate, a recording layercomprising at least one of the compounds of formula (I), a reflectorlayer and a covering layer, the writing and readout being effectedthrough the substrate.

Suitable substrates are, for example, glass, minerals, ceramics andthermosetting and thermoplastic plastics. Preferred supports are glassand homo- or co-polymeric plastics. Suitable plastics are, for example,thermoplastic polycarbonates, polymides, polyesters, polyacrylates andpolymethacrylates, polyurethanes, polyolefins, polyvinyl chloride,polyvinylidene fluoride, polyimides, thermosetting polyesters and epoxyresins. Special preference is given to polycarbonate substrates whichcan be produced, for example, by injection-moulding. The substrate canbe in pure form or may comprise customary additives, for example UVabsorbers or dyes, as proposed e.g. in JP-A-04/167239 as lightstabilisation for the recording layer. In the latter case it may be thatin the range of the writing wavelength (emission wavelength of thelaser) the dye added to the support substrate has no or at most onlyvery low absorption, preferably up to a maximum of about 20% of thelaser light focussed onto the recording layer.

The substrate is advantageously transparent over at least a portion ofthe range from 350 to 500 nm, so that it is permeable to, for example,at least 80% of the incident light of the writing or readout wavelength.The substrate is advantageously from 10 μm to 2 mm thick, preferablyfrom 100 to 1200 μm thick, especially from 600 to 1100 μm thick, with apreferably spiral guide groove (track) on the coating side, a groovedepth of from 10 to 200 nm, preferably from 80 to 150 nm, a groove widthof from 100 to 400 nm, preferably from 150 to 250 nm, and a spacingbetween two turns of from 200 to 600 nm, preferably from 350 to 450 nm.Grooves of different cross-sectional shape are known, for examplerectangular, trapezoidal or V-shaped. Analogously to the known CD-R andDVD-R media, the guide groove may additionally undergo a small periodicor quasi-periodic lateral deflection (wobble), so that synchronisationof the speed of rotation and the absolute positioning of the readinghead (pick-up) are made possible. Instead of, or in addition to, thedeflection, the same function can be performed by markings betweenadjacent grooves (pre-pits).

The recording medium is applied, for example, by application of asolution by spin-coating, the objective being to produce a layer that isas amorphous as possible, the thickness of which layer is advantageouslyfrom 0 to 40 nm, preferably from 1 to 20 nm, especially from 2 to 10 nm,on the surface (“land”) and, depending upon the geometry of the groove,advantageously from 20 to 150 nm, preferably from 50 to 120 nm,especially from 60 to 100 nm, in the groove.

Reflecting materials suitable for the reflector layer include especiallymetals, which provide good reflection of the laser radiation used forrecording and playback, for example the metals of Main Groups III, IVand V and of the Sub-Groups of the Periodic Table of the Elements. Al,In, Sn, Pb, Sb, Bi, Cu, Ag, Au, Zn, Cd, Hg, Sc, Y, La, Ti, Zr, Hf, V,Nb, Ta, Cr, Mo, W, Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt and the lanthanidemetals Ce, Pr, Nd, Pm, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb and Lu andalloys thereof are especially suitable. On account of its highreflectivity and ease of production special preference is given to areflective layer of aluminium, silver, gold or an alloy thereof (forexample a white gold alloy), especially aluminium on economic andecological grounds. The reflector layer is advantageously from 5 to 200nm thick, preferably from 10 to 100 nm thick, especially from 40 to 60nm thick, but reflector layers of greater thickness, for example 1 mmthick or even more, are also possible.

Materials suitable for the covering layer include chiefly plastics,which are applied in a thin layer to the reflector layer either directlyor with the aid of adhesion promoters. It is advantageous to selectmechanically and thermally stable plastics having good surfaceproperties, which can be modified further, for example written on. Theplastics may be thermosetting plastics and thermoplastic plastics.Directly applied covering layers are preferably radiation-cured (e.g.using UV radiation) coatings, which are particularly simple andeconomical to produce. A wide variety of radiation-curable materials areknown. Examples of radiation-curable monomers and oligomers areacrylates and methacrylates of diols, triols and tetrols, polyimides ofaromatic tetracarboxylic acids and aromatic diamines having C₁-C₄alkylgroups in at least two ortho-positions of the amino groups, andoligomers with dialkylmaleinimidyl groups, e.g. dimethylmaleinimidylgroups. For covering layers that are applied using adhesion promoters itis preferable to use the same materials as those used for the substratelayer, especially polycarbonates. The adhesion promoters used arepreferably likewise radiation-curable monomers and oligomers. Instead ofthe covering layer applied using an adhesion promoter there may also beused a second substrate comprising a recording and reflector layer, sothat the recording medium is playable on both sides. Preference is givento a symmetrical structure, the two parts being joined together at thereflector side by an adhesion promoter directly or by way of anintermediate layer.

In such a structure, the optical properties of the covering layer, orthe covering materials, are essentially unimportant per se providedthat, where applicable, curing thereof e.g. by UV radiation is achieved.The function of the covering layer is to ensure the mechanical strengthof the recording medium as a whole and, if necessary, the mechanicalstrength of thin reflector layers. If the recording medium issufficiently robust, for example when a thick reflector layer ispresent, it is even possible to dispense with the covering layeraltogether. The thickness of the covering layer depends upon thethickness of the recording medium as a whole, which should preferably bea maximum of about 2 mm thick The covering layer is preferably from 10μm to 1 mm thick.

The recording media according to the invention may also have additionallayers, for example interference layers or barrier layers. It is alsopossible to construct recording media having a plurality of (for examplefrom two to ten) recording layers. The structure and the use of suchmaterials are known to the person skilled in the art. Where present,interference layers are preferably arranged between the recording layerand the reflecting layer and/or between the recording layer and thesubstrate and consist of a dielectric material, for example as describedin EP-A-0 353 393 of TiO₂, Si₃N₄, ZnS or silicone resins.

The recording media according to the invention can be produced byprocesses known per se, it being possible for various methods of coatingto be employed depending upon the materials used and their function.

Suitable coating methods are, for example, immersion, pouring,brush-coating, blade-application and spin-coating, as well asvapour-depositon methods carried out under a high vacuum. When, forexample, pouring methods are used, solutions in organic solvents aregenerally employed. When solvents are employed, care should be takenthat the supports used are insensitive to those solvents. Suitablecoating methods and solvents are described, for example, in EP-A-0 401791.

The recording layer is applied preferably by the application of a dyesolution by spin-coating, solvents that have proved satisfactory beingespecially alcohols, e.g. 2-methoxyethanol, isopropanol or n-butanol,hydroxyketones, for example diacetone alcohol or3-hydroxy-3-methyl-2-butanone, hydroxy esters, for example lactic acidmethyl ester or isobutyric acid methyl ester, or preferably fluorinatedalcohols, for example 2,2,2-trifluoroethanol or2,2,3,3-tetrafluoro-1-propanol, and mixtures thereof. Further suitablesolvents are disclosed, for example, in EP-A-0 483 387.

The application of the metallic reflector layer is preferably effectedby sputtering or by vapour-deposition in vacuo. Such techniques areknown and are described in specialist literature (e.g. J. L. Vossen andW. Kern, “Thin Film Processes”, Academic Press, 1978). The operation canadvantageously be carried out continuously and achieves goodreflectivity and a high degree of adhesiveness of the metallic reflectorlayer.

Recording is carried out in accordance with known methods by writingpits (marks) of fixed or variable length by means of a modulated,focussed laser beam guided at a constant or variable speed over thesurface of the recording layer. Readout of information is carried outaccording to methods known per se by registering the change inreflection using laser radiation, for example as described in “CD-Playerand R-DAT Recorder” (Claus Biaesch-Wiepke, Vogel Buchverlag, Würzburg1992).The person skilled in the art will be familiar with therequirements.

The information-containing medium according to the invention isespecially an optical information material of the WORM type. It can beused, for example, analogously to CD-R (compact disc—recordable) orDVD-R (digital video disc—recordable) in computers, and also as storagematerial for identification and security cards or for the production ofdiffractive optical elements, for example holograms.

Alternatively, however, there are also recording media which differsubstantially from CDR and DVD-R and in which recording and playbacktake place not through the substrate but through the covering layer(“in-groove recording”). Accordingly the respective roles of thecovering layer and the substrate, especially the geometry and theoptical properties, are reversed in comparison with the structuredescribed above. Analogous concepts are described a number of times inProceedings SPIE-Int Soc. Opt Eng. 1999, 3864 for digital videorecordings in conjunction with a blue GaN laser diode. For suchrecording media, which are especially suitable for a high storagedensity and have correspondingly small marks (“pits”), precise focussingis important, so that the manufacturing process, while essentiallyanalogous, is considerably more awkward.

The compounds of formula (I) according to the invention, however, alsomeet the increased demands of an inverse layer structure surprisinglywell. Preference is therefore given to an inverse layer structure havingthe layer sequence substrate, reflector layer, recording layer andcovering layer. The recording layer is therefore located between thereflector layer and the covering layer. A thin covering layerapproximately from 50 to 400 μm in thickness is especially advantageous(typically 100 μm at a numerical aperture of 0.85).

The recording and reflector layers in an inverse layer structure have inprinciple the same functions as indicated above. As with the groovegeometry, they therefore usually have dimensions within the rangesindicated above.

The inverse layer structure requires particularly high standards, whichthe compounds used according to the invention fulfill astonishinglywell, for example when the recording layer is applied to the metallicreflector layer and especially when a covering layer is applied to therecording layer, the covering layer being required to provide therecording layer with adequate protection against rubbing,photooxidation, fingerprints, moisture and other environmental effectsand advantageously having a thickness in the range of from 0.01 to 0.5mm, preferably in the range of from 0.05 to 0.2 mm, especially in therange of from 0.08 to 0.13 mm.

The covering layer preferably consists of a material that exhibits atransmission of 80% or above at the writing or readout wavelength of thelaser. Suitable materials for the covering layer include, for example,those materials mentioned above, but especially polycarbonate (such asPure Ace® or Panlite®, Teijin Ltd), cellulose triacetate (such asFujitac®, Fuji Photo Film) or polyethylene terephthalate (such asLumirror®, Toray Industry), special preference being given topolycarbonate. Especially in the case of directly applied coveringlayers, radiation-cured coatings, such as those already described above,are advantageous, for example SD 347™ (Dainippon Ink).

The covering layer can be applied directly to the solid recording layerby means of a suitable adhesion promoter. In another embodiment, thereis applied to the solid recording layer an additional, thin separatinglayer of a metallic, crosslinked organometallic or preferably dielectricinorganic material, for example in a thickness of from 0.001 to 10 μm,preferably from 0.005 to 1 μm, especially from 0.01 to 0.1 μm, forexample from 0.05 to 0.08 μm in the case of dielectric separating layersand from 0.01 to 0.03 μm in the case of metallic separating layers.Separating layers and corresponding methods are disclosed in WO02/082438, to which reference is expressly made here. If desired, suchcoatings can be applied, for example, in the same thickness also betweenthe support material and the metallic reflector layer or between themetallic reflector layer and the optical recording layer. This may beadvantageous in certain cases, for example when a silver reflector isused in combination with sulfur-containing additives in the recordinglayer.

In a special variant, there is applied to the solid recording layer anadditional, thin separating layer of a metallic, crosslinkedorganometallic or dielectric inorganic material, for example in athickness of from 0.001 to 10 μm, preferably from 0.005 to 1 μm,especially from 0.01 to 0.1 μm. On account of their high reflectivity,metallic separating layers should advantageously be a maximum of 0.03 μmthick.

Separating layers and corresponding methods are disclosed in WO02/082438, to which reference is expressly made here.

Some of the compounds used according to the invention are known,especially from J. Org. Chem. 67/16, 5753-5772 [2002].

It is also possible, however, to prepare analogously to the knowncompounds new compounds that can be used in accordance with theinvention in optical recording media.

The invention therefore relates also to compounds of formula (I), withthe exception of the already known compounds of formula M₂(Z₁)₂,wherein:

Reference is made especially to compounds of formulae

and to compounds wherein M₂ is Cu, Co, Ni or Pd and Z₁ is a radical ofthe following compounds:

Especially interesting properties are exhibited by the preferredcompounds of formulae

also mixtures of compounds of formula (II) and/or (III), whereinespecially G₁ and G₂ are the preferred heterocycles disclosed above andat the same time or independently thereof M₁ is a preferred transitionmetal. A₃ in G₁ and G₂ can be especially N(R₁₂), O, S or, especially informula (III), C(C₁-C₅alkyl)₂.

Special preference is given to compounds of formula

and mixtures thereof wherein A₄, independently of A₃, has the samedefinition and the same preferred meanings as A₃.

Very special preference is given to compounds of formula

Both in formula (IV) and in formula (V), R₃₂, R₃₃, R₃₄, R₃₅, R₃₆, R₃₇,R₃₈ and R₃₉ are preferably H, C₁-C₄alkyl, COO—C₁-C₄alkyl, CN, NO₂, CHO,COC₁-C₄alkyl, phenyl, CH[—O—C₂-C₃alkylene-O—],C(C₁-C₄alkyl)[—O—C₂-C₃alkylene-O—], CH═C(CN)₂, C(CN)═C(CN)₂orC(C₁-C₄alkyl)═C(CN)₂, especially H, CH₃, C₂H₅, COOCH₃, COOC₂H₅, CN, NO₂or CHO.

Compounds of formula (IV) are, for example, the following: N^(o) FormulaA₁ = A₂ A₃ = A₄ Q₁ = Q₂ R₃₂ = R₃₈ R₃₃ = R₃₇ R₃₄ = R₃₈ R₃₅ = R₃₉ M₁ D1(IV) NCH₃ O N H H H H Co²⁺ D2 (IV) NCH₂CH₃ O N CH₃ H CH₃ H Co²⁺ D3 (IV)NCH₂CH₃ O N CH₃ H H H Co²⁺ D4 (IV) S O N NO₂ H H H Co²⁺ D5 (IV) S O NNO₂ H CH₃ H Co²⁺ D6 (IV) NCH₃ NCH₃ N NO₂ H NO₂ H Co²⁺ D7 (IV) NCH₂CH₃NCH₂CH₃ N CN H CN H Co²⁺ D8 (IV) S NCH₂CH₃ N H H H H Co²⁺ D9 (IV) O O CHNO₂ H NO₂ H Co²⁺ D10 (IV) O O CH CN H CN H Co²⁺ D11 (IV) O O CH SCH₃ HSCH₃ H Co²⁺ D12 (IV) S S N t-C₄H₉ H t-C₄H₉ H Co²⁺ D13 (IV) S S N CHO HCHO H Co²⁺ D14 (IV) S S N H i-C₃H₇ H i-C₃H₇ Co²⁺ D15 (IV) S S N CHC(CN)₂H CHC(CN)₂ H Co²⁺ D16 (IV) NCH₃ O N H H H H Cu²⁺ D17 (IV) NCH₂CH₃ O NCH₃ H CH₃ H Cu²⁺ D18 (IV) NCH₂CH₃ O N CH₃ H H H Ni²⁺ D19 (IV) S O N NO₂H H H Cu²⁺ D20 (IV) S O N NO₂ H CH₃ H Cu²⁺ D21 (IV) NCH₃ NCH₃ N NO₂ HNO₂ H Ni²⁺ D22 (IV) NCH₂CH₃ NCH₂CH₃ N CN H CN H Cu²⁺ D23 (IV) S NCH₂CH₃N H H H H Cu²⁺ D24 (IV) O O CH NO₂ H NO₂ H Ni²⁺ D25 (IV) O O CH CN H CNH Cu²⁺ D26 (IV) O O CH SCH₃ H SCH₃ H Cu²⁺ D27 (IV) S S N t-C₄H₉ H t-C₄H₉H Ni²⁺ D28 (IV) S S N CHO H CHO H Cu²⁺ D29 (IV) S S N H i-C₃H₇ H i-C₃H₇Cu²⁺ D30 (IV) S S N CHC(CN)₂ H CHC(CN)₂ H Ni²⁺

Compounds of formula (V) are, for example, the following: N^(o) FormulaR₃₂ = R₃₆ R₃₃ = R₃₇ R₃₄ = R₃₈ R₃₅ = R₃₉ M₁ D31 (V) H H H H Co²⁺ D32 (V)CH₃ H CH₃ H Co²⁺ D33 (V) CH₃ H H H Co²⁺ D34 (V) H CH₃ H CH₃ Co²⁺ D35 (V)H H H CH₃ Co²⁺ D36 (V) CH₂CH₃ H CH₂CH₃ H Co²⁺ D37 (V) CH₂CH₃ H H H Co²⁺D38 (V) n-C₃H₇ H n-C₃H₇ H Co²⁺ D39 (V) n-C₃H₇ H H H Co²⁺ D40 (V) i-C₃H₇H i-C₃H₇ H Co²⁺ D41 (V) i-C₃H₇ H H H Co²⁺ D42 (V) n-C₄H₉ H n-C₄H₉ H Co²⁺D43 (V) n-C₄H₉ H H H Co²⁺ D44 (V) i-C₃H₇ CH₃ i-C₃H₇ CH₃ Co²⁺ D45 (V) H Hi-C₃H₇ CH₃ Co²⁺ D46 (V) H i-C₄H₉ H i-C₄H₉ Co²⁺ D47 (V) H i-C₄H₉ H H Co²⁺D48 (V) COOCH₂CH₃ CH₃ COOCH₂CH₃ CH₃ Co²⁺ D49 (V) COOCH₂CH₃ CH₃ H H Co²⁺D50 (V) H COOCH₂CH₃ H H Co²⁺ D51 (V) H COOCH₂CH₃ H COOCH₂CH₃ Co²⁺ D52(V) CH═C(CN)₂ H CH═C(CN)2 H Co²⁺ D53 (V) NO₂ H NO₂ H Co²⁺ D54 (V) H H HH Cu²⁺ D55 (V) CH₃ H CH₃ H Cu²⁺ D56 (V) CH₃ H H H Cu²⁺ D57 (V) H CH₃ HCH₃ Cu²⁺ D58 (V) H H H CH₃ Cu²⁺ D59 (V) CH₂CH₃ H CH₂CH₃ H Cu²⁺ D60 (V)CH₂CH₃ H H H Cu²⁺ D61 (V) n-C₃H₇ H n-C₃H₇ H Cu²⁺ D62 (V) n-C₃H₇ H H HCu²⁺ D63 (V) i-C₃H₇ H i-C₃H₇ H Cu²⁺ D64 (V) i-C₃H₇ H H H Cu²⁺ D65 (V)n-C₄H₉ H n-C₄H₉ H Cu²⁺ D66 (V) n-C₄H₉ H H H Cu²⁺ D67 (V) i-C₃H₇ CH₃i-C₃H₇ CH₃ Cu²⁺ D68 (V) H H i-C₃H₇ CH₃ Cu²⁺ D69 (V) H i-C₄H₉ H i-C₄H₉Cu²⁺ D70 (V) H i-C₄H₉ H H Cu²⁺ D71 (V) COOCH₂CH₃ CH₃ COOCH₂CH₃ CH₃ Cu²⁺D72 (V) COOCH₂CH₃ CH₃ H H Cu²⁺ D73 (V) H COOCH₂CH₃ H H Cu²⁺ D74 (V) HCOOCH₂CH₃ H COOCH₂CH₃ Cu²⁺ D75 (V) CH═C(CN)₂ H CH═C(CN)₂ H Cu²⁺ D76 (V)NO₂ H NO₂ H Cu²⁺ D77 (V) H H H H Ni²⁺ D78 (V) CH₃ H CH₃ H Ni²⁺ D79 (V)CH₃ H H H Ni²⁺ D80 (V) H CH₃ H CH₃ Ni²⁺ D81 (V) H H H CH₃ Ni²⁺ D82 (V)CH₂CH₃ H CH₂CH₃ H Ni²⁺ D83 (V) CH₂CH₃ H H H Ni²⁺ D84 (V) n-C₃H₇ H n-C₃H₇H Ni²⁺ D85 (V) n-C₃H₇ H H H Ni²⁺ D86 (V) i-C₃H₇ H i-C₃H₇ H Ni²⁺ D87 (V)i-C₃H₇ H H H Ni²⁺ D88 (V) n-C₄H₉ H n-C₄H₉ H Ni²⁺ D89 (V) n-C₄H₉ H H HNi²⁺ D90 (V) i-C₃H₇ CH₃ i-C₃H₇ CH₃ Ni²⁺ D91 (V) H H i-C₃H₇ CH₃ Ni²⁺ D92(V) H i-C₄H₉ H i-C₄H₉ Ni²⁺ D93 (V) H i-C₄H₉ H H Ni²⁺ D94 (V) COOCH₂CH₃CH₃ COOCH₂CH₃ CH₃ Ni²⁺ D95 (V) COOCH₂CH₃ CH₃ H H Ni²⁺ D96 (V) HCOOCH₂CH₃ H H Ni²⁺ D97 (V) H COOCH₂CH₃ H COOCH₂CH₃ Ni²⁺ D98 (V)CH═C(CN)₂ H CH═C(CN)₂ H Ni²⁺ D99 (V) NO₂ H NO₂ H Ni²⁺

Instead of pure compounds it is also possible to use mixtures thereof,for example the following mixtures: N^(o) % % % % % M1 D54 80 D77 20 M2D32 5 D54 80 D77 15 M3 D54 80 D55 10 D78 10 M4 D54 80 D56 15 D79 5 M5D54 80 D55 10 D56 10 M6 D54 80 D56 20 M7 D54 80 D56 15 D79 5 M8 D54 90D57 10 M9 D54 80 D57 10 D81 10 M10 D54 80 D58 20 M11 D54 80 D57 10 D5810 M12 D54 65 D57 10 D58 5 D77 15 D81 5 M13 D54 90 D59 10 M14 D54 80 D6020 M15 D54 70 D59 5 D60 10 D76 5 D82 5 M16 D56 90 D61 10 M17 D56 90 D6210 M18 D54 90 D68 10 M19 D54 90 D71 10 M20 D54 75 D72 15 D76 5 D95 5 M21D54 70 D73 20 D76 5 D96 5 M22 D54 80 D74 20 M23 D54 80 D55 5 D56 5 D57 5D76 5 M24 M5 50 M14 30 D58 5 D76 5 D77 10

Instead of preparing mixtures by mixing together the components, it isfavourably possible to prepare mixtures by mixed synthesis, the metalsbeing added in any desired order in succession or preferablysimultaneously to a pre-prepared mixture of the ligands, or converselythe ligands being added in any desired order in succession or preferablyall of them simultaneously to a pre-prepared mixture of the metals. Themixtures prepared by mixed synthesis generally have somewhat bettersolubility than physical mixtures, possibly because of their asymmetriccomponents.

In addition to comprising one or more compounds of formula (I) andoptionally customary additives, the optical recording media according tothe invention may also comprise other chromophores, preferablymetal-free chromophores. Other chromophores may, if desired, be added inan amount of from 1 to 200% by weight, based on the total of thecompounds of formula (I). The amount of other chromophores is preferablyfrom 5 to 100% by weight, especially from 10 to 50% by weight, based onthe total of the compounds of formula (I). Chromophores can be dyes orUV absorbers, preferably having an absorption maximum of from 350 to 400nm or at from 600 to 700 nm, for example around 380 or 630 nm.

Especially preferred additional metal-free chromophores are cyanines,azacyanines, merocyanines and oxonols and also rhodamines, for examplethose disclosed in WO 04/006878, WO 02/082438 or EP-A-1 083 555, andalso

wherein R₄₀ is C₁-C₂₄alkyl or C₂-C₂₄alkenyl, each of which can beunsubstituted or substituted, and R₄₁ is any substituent R₄₀ may be, forexample, methyl, ethyl, vinyl, allyl, isopropyl, n-butyl,2-isopropyloxyethyl, n-pentyl, 3-methyl-butyl, 3,3-dimethyl-butyl,2-ethyl-hexyl, 2-cyano-ethyl, furan-2-ylmethyl or 2-hydroxy-methyl; R₄₁is, for example, C₆-C₁₀aryl, C₁-C₂₄alkyl or C₂-C₂₄alkenyl.

Purely illustrative examples of such chromophores are:

The following Examples illustrate the invention but do not limit thescope thereof (unless otherwise indicated, “%” always refers to % byweight):

EXAMPLE 1

1.0 g of the compound of formula

is applied in the form of a dichloromethane solution to glass. The solidlayer is irradiated for 90 hours with xenon light according toISO-105-B02 (Atas Ci-35 Weather-O-meter, 15 kJ/cm²). The light stabilityis excellent (see Example 7).

EXAMPLE 2

On the solid layer according to Example 1, marks are written into therecording layer using a pulsed dye laser (15 ns pulse length) at awavelength of 405 nm at an energy density of 0.8 kJ/m². The writtensites exhibit a resulting change in reflectivity.

EXAMPLE 3

0.5 g of the compound according to Example 1 is dissolved in 99.5 g ofdioxane and applied by means of spin-coating to a silicon wafer. Thecolourless solid layer is measured using a spectral ellipsometer(Sopra). At a wavelength of 405 nm a refractive index of 2.52 isdetermined.

EXAMPLE 4

1.0 g of the compound of formula

dissolved in 99 g of methylcydohexane and filtered through a 0.2 μmTeflon filter. The dye solution is then applied by rotation at 250rev/min to a 1.2 mm thick, flat polycearbonate plate (diameter 120 mm).The rotational speed is then increased to 1200 rev/min, so that theexcess solution is spun off, and a uniform solid layer is formed. Afterdrying, the solid layer has an absorption of 0.61 at 382 nm. Using anoptical measuring system (ETA-RT, STEAG ETA-Optk), the layer thicknessand the complex refractive index are determined. At 405 nm the dye layerhas a layer thickness of 56 nm, a refractive index n of 1.95 and anextinction coefficient k of 0.090.

EXAMPLE 5

Synthesis of the Ligand

19.4 ml of a 55% aqueous chloracetaldehyde solution are added to asuspension of 10.2 g of dithiobiuret in 45 ml of ethanol. The reactionmixture is heated at 75° C. for 2 hours, and then poured into 150 ml ofwater. After the addition of 200 ml of an aqueous sodium acetatesolution (4.6N), the precipitate is filtered off, washed with water anddried at 50° C./1.5·10³ Pa, yielding 8.8 g of crude product, and afterrecrystallisation from ethanol 6.7 9 of pure product of formula

(m.p. 212° C.).Synthesis of the Complex

0.5N aqueous copper(II) acetate solution is added to a solution of 458mg of the resulting ligand in 30 ml of ethanol until precipitation,which begins immediately, is complete. After filtration, the product iswashed with ethanol and diethyl ether, and then dried at 70° C./1.5·10³Pa. 390 mg of pure product of formula

(decomp. 264° C.) are obtained.

EXAMPLE 6

1.0 g of the complex according to Example 5 is dissolved in 99 g of2,2,3,3-tetrafluoro-1-propanol and filtered through a 0.2 μm Teflonfilter. The dye solution is then applied by rotation at 250 rev/min to a1.2 mm thick, flat poly-carbonate plate (diameter 120 mm); therotational speed is then increased to 1500 rev/min, so that the excesssolution is spun off and a uniform solid layer is formed. After drying,the solid layer has an absorption of 0.35 at 356 nm. Using an opticalmeasuring system (ETA-RT, STEAG ETA-Optik), the layer thickness and thecomplex refractive index are determined. At 405 nm the dye layer has alayer thickness of 18 nm, a refractive index n of 2.25 and an extinctioncoefficient k of 0.031.

EXAMPLES 7-38

The procedure is analogous to Example 6, but instead of the complex ofExample 5 the following ligands and metal cations are used: λ_(max)Metal Ligand (2x) [nm] Solvent n k Cu²⁺

370 CH₃CN (+HCl) 2.52 0.47 Cu²⁺

383 CH₂Cl₂ 2.30 0.185 Ni²⁺

370 CH₂Cl₂ 2.23 0.160 Cu²⁺

390 CH₂Cl₂ 2.22 0.266 Cu²⁺

377 CH₂Cl₂ 2.21 0.244 Co²⁺

370 CH₂Cl₂ 2.20 0.137 Co²⁺

376 CH₂Cl₂ 2.19 0.179 Ni²⁺

361 CH₂Cl₂ 2.17 0.108 Co²⁺

370 CH₂Cl₂ 2.08 0.158 Ni²⁺

361 CH₂Cl₂ 2.07 0.097 Cu²⁺

384 CH₂Cl₂ 2.00 0.092 Co²⁺

351 CH₂Cl₂ 1.98 0.100 Co²⁺

370 CH₂Cl₂ 1.94 0.083 Ni²⁺

350 CH₂Cl₂ 1.93 0.083 Co²⁺

367 CH₂Cl₂ 1.83 0.103 Ni²⁺

368 CH₂Cl₂ 1.74 0.119 Cu²⁺

369 CH₂Cl₂ Ni²⁺

350 CH₂Cl₂ Co²⁺

348 CH₂Cl₂ Ni²⁺

356 CH₃CN Ni²⁺

357 CH₂Cl₂ Co²⁺

364 CH₂Cl₂ Co²⁺

370 CH₃CN (+HCl) Ni²⁺

370 CH₃CN (+HCl) Cu²⁺

374 CH₂Cl₂ Ni²⁺

374 CH₂Cl₂ Co²⁺

376 CH₃CN Cu²⁺

387 CH₂Cl₂ Ni²⁺

Co²⁺

350 CH₂Cl₂ Cu²⁺

358 CH₂Cl₂

EXAMPLES 39-62

The procedure is analogous to Example 6, but instead of the complex ofExample 5 the mixtures M1 to M24 are used.

EXAMPLES 63-86

The procedure is analogous to Example 6, but instead of the complex ofExample 5 there are used mixtures having the same proportions of metaland ligand as mixtures M1 to M24 but the complexes are prepared by mixedsynthesis (variant of the simultaneous addition of the metal mixture tothe ligand mixture). The results are similar to those of Examples 39-62,but have surprisingly better solubility and solution stability.

EXAMPLES 87-94

The procedure is analogous to Example 6, but instead of the complex ofExample 5 there are used the following mixtures of compounds of formula(I) with cyanines and merocyanines:

It will be understood that it is also possible to combine mixtures ofthose cyanines, merocyanines and/or also other chromophores withcomplexes of formula (I) or with mixtures of complexes of formula (I),the results achieved generally being very good.

1. An optical recording medium comprising a substrate, a recording layerand optionally one or more reflecting layers, wherein the recordinglayer comprises a compound of formula

or a tautomer thereof, wherein G₁ and G₂ are each independently of theother

A₁ and A₂ are each independently of the other N(R₁₂), O, S or Se and A₃is C(C₁-C₅alkyl)₂, C(C₄-C₅alkylene), N(R₁₂), O, S, Se, N═C(R₁₃) orunsubstituted or R₁₄-substituted CH═CH; M₁ is a transition metal ofgroups IX to XII; Q₁ and Q₂ are each independently of the other C(R₁₅),N or P; R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈ and R₁₄ are each independently ofthe others hydrogen, R₁₈, or C₆-C₁₂aryl, C₄-C₁₂heteroaryl, C₇-C₁₂aralkylor C₅-C₁₂heteroaralkyl each unsubstituted by one or more, whereapplicable identical or different, radicals R₁₈; or R₁ and R₂, R₃ andR₄, R₅ and R₆, R₅ and R₁₃ and/or R₅ and R₁₄, together in pairs, areC₃-C₆alkylene or C₃-C₆alkenylene, each of which is unsubstituted orsubstituted by one or more, where applicable identical or different,radicals R₁₇ and may be uninterrupted or interrupted by O, S or N(R₁₂),or 1,4-buta-1,3-dienylene,

each of which is unsubstituted or substituted by one or more, whereapplicable identical or different, radicals R₁₈ and in which 1 or 2carbon atoms may have been replaced by nitrogen; R₉, R₁₂ and R₁₃ areeach independently of the others C₁-C₂₄alkyl, C₃-C₂₄cycloalkyl,C₂-C₂₄alkenyl, C₃-C₂₄cycloalkenyl, C₁-C₄alkyl-[O—C₁-C₄alkylene]_(m) orC₁-C₄alkyl-[NH—C₁-C₄alkylene]_(m), each of which is unsubstituted orsubstituted by one or more, where applicable identical or different,radicals R₁₇; or C₆-C₁₂aryl, C₄-C₁₂heteroaryl, C₇-C₁₂aralkyl orC₅-C₁₂heteroaralkyl, each of which is unsubstituted or substituted byone or more, where applicable identical or different, radicals R₁₈; R₁₀,R₁₁ and R₁₈ are each independently of the others halogen, nitro, cyano,thiocyanato, hydroxy, O—R₁₉, O—CO—R₁₉, S—R₁₉, CHO, COR₂₀, CHOR₁₉OR₂₃,CR₂₀OR₁₉OR₂₃, R₁₆, N═N—R₁₆, N═CR₁₉R₂₀, N═CR₂₁R₂₂, C(R₁₅)═NR₁₉,C(R₁₅)═NR₂₁, C(R₁₅)═CR₂₁R₂₂, NH₂, NH—R₁₉, NR₁₉R₂₀, NH₃ ⁺, NH₂R₁₉ ⁺,NHR₁₉R₂₀ ⁺, NR₁₉R₂₀R₂₃ ⁺, CONH₂, CONHR₁₉, CONR₁₉R₂₀, SO₂R₁₉, SO₂NH₂,SO₂NHR₁₉, SO₂NR₁₉R₂₀, COOH, COOR₁₉, OCOOR₁₉, NHCOR₁₉, NR₁₉COR₂₃,NHCOOR₁₉, NR₁₉COOR₂₃, ureido, NR₁₉—CO—NHR₂₃, B(OH)₂, B(OH)(OR₁₉),B(OR₁₉)OR₂₃, phosphate, PR₁₉R₂₃, POR₁₉OR₂₃, P(═O)OR₁₉OR₂₃, OPR₁₉R₂₃,OPR₁₉OR₂₃, OP(═O)R₁₉OR₂₃, OP(═O)OR₁₉OR₁₉OR₂₃, OPO₃R₁₉, sulfato, sulfo,or C₁-C₁₂alkyl, C₃-C₁₂cycloalkyl, C₁-C₁₂alkylthio, C₃-C₁₂cycloalkylthio,C₁-C₁₂alkoxy or C₃-C₁₂cycloalkoxy each unsubstituted or substituted byone or more, where applicable identical or different, radicals R₁₇; R₁₅is hydrogen, cyano, hydroxy, C₁-C₁₂alkoxy, C₃-C₁₂cycloalkoxy,C₁-C₁₂alkylthio, C₃-C₁₂cycloalkylthio, amino, NHR₂₄, NR₂₅R₂₆, R₂₇,halogen, nitro, formyl, N═N—R₂₇, C(R₁₄)═CR₂₁R₂₂, C(R₁₄)═NR₁₉, COO—R₂₅,carboxy, carbamoyl, CONH—R₂₅, CONR₂₅R₂₆, N═CR₁₉R₂₀, or C₁-C₁₂alkyl,C₃-C₁₂cycloalkyl, C₂-C₁₂alkenyl or C₃-C₁₂cycloalkenyl each unsubstitutedor substituted by one or more, where applicable identical or different,halogen, hydroxy, C₁-C₁₂alkoxy or C₃-C₁₂cycloalkoxy radicals; R₁₆ isC₆-C₁₂aryl, C₄-C₁₂heteroaryl, C₇-C₁₂aralkyl or C₅-C₁₂heteroaralkyl, eachof which is unsubstituted or substituted by one or more, whereapplicable identical or different, radicals R₂₈; R₁₇ is halogen,hydroxy, O—R₂₅, O—CO—R₂₅, S—R₂₅, NH₂, NH—R₂₅, NR₂₅R₂₆, NH₃ ⁺, NH₂R₂₅ ⁺,NHR₂₅R₂₆ ⁺, NR₂₄R₂₅R₂₆ ⁺, NR₂₅—CO—R₂₄, NR₂₅COOR₂₄, cyano, formyl,COO—R₂₅, carboxy, carbamoyl, CONH—R₂₅, CONR₂₅R₂₆, ureido, NH—CO—NHR₂₄,NR₂₅—CO—NHR₂₄, phosphate, PR₂₅R₂₄, POR₂₅OR₂₄, P(═O)OR₂₅OR₂₄, OPR₂₅R₂₄,OPR₂₅OR₂₄, OP(═O)R₂₅OR₂₄, OPO₃R₂₅, OP(═O)OR₂₅OR₂₄, SO₂R₂₅, sulfato,sulfo, R₂₇, N═N—R₂₇, or C₁-C₁₂alkoxy or C₁-C₁₂cycloalkoxy eachunsubstituted or mono- or poly-substituted by halogen; R₁₉, R₂₀ and R₂₃are each independently of the others R₁₆, or C₁-C₁₂alkyl,C₃-C₁₂cycloalkyl, C₂-C₁₂alkenyl or C₃-C₁₂cycloalkenyl, each of which isunsubstituted or substituted by one or more, where applicable identicalor different, halogen, hydroxy, C₁-C₁₂alkoxy or C₃-C₁₂cycloalkoxyradicals; or R₁₄ and R₁₉ together, R₁₅ and R₁₉ together and/or R₁₉ andR₂₃ together are C₂-C₁₂alkylene, C₃-C₁₂cycloalkylene, C₂-C₁₂alkenyleneor C₃-C₁₂cycloalkenylene, each of which is unsubstituted or substitutedby one or more, where applicable identical or different, halogen,hydroxy, C₁-C₁₂alkoxy or C₃-C₁₂cycloalkoxy radicals; or R₁₉ and R₂₀together with the common nitrogen are pyrrolidine, piperidine,piperazine or morpholine, each of which is unsubstituted or mono- totetra-substituted by C₁-C₄alkyl; or carbazole, phenoxazine orphenothiazine, each of which is unsubstituted or substituted by one ormore, where applicable identical or different, radicals R₂₈; R₂₁ and R₂₂are each independently of the other NR₂₅R₂₆, CN, CONH₂, CONHR₁₉,CONR₁₉R₂₀ or COOR₂₀; R₂₄, R₂₅ and R₂₆ are each independently of theothers C₁-C₁₂alkyl, C₃-C₁₂cycloalkyl, C₂-C₁₂alkenyl, C₃-C₁₂cycloalkenyl,C₆-C₁₂aryl, C₄-C₁₂heteroaryl, C₇-C₁₂aralkyl or C₅-C₁₂heteroaralkyl; orR₂₅ and R₂₆ together with the common nitrogen are pyrrolidine,piperidine, piperazine or morpholine, each of which is unsubstituted orsubstituted by from 1 to 4 C₁-C₄alkyl; R₂₇ is C₆-C₁₂aryl,C₄-C₁₂heteroaryl, C₇-C₁₂aralkyl or C₅-C₁₂heteroaralkyl, each of which isunsubstituted or substituted by one or more, where applicable identicalor different, radicals R₁₈; R₂₈ is nitro, SO₂NHR₂₅, SO₂NR₂₅R₂₆, orC₁-C₁₂alkyl, C₃-C₁₂cycloalkyl, C₁-C₁₂alkylthio, C₃-C₁₂cycloalkylthio,C₁-C₁₂alkoxy or C₃-C₁₂cycloalkoxy, each of which is unsubstituted orsubstituted by one or more, where applicable identical or different,radicals R₁₇; and m is a number from 1 to
 10. 2. An optical recordingmedium according to claim 1, wherein Q₁ and Q₂ are C(R₁₅); G₁ and G₂ are

and A₁, A₂ and A₃ are O, S or N(R₁₂); R₁₂ is C₁-C₂₄alkyl,C₁-C₄alkyl-[O—C₁-C₄alkylene]_(m) or C₁-C₄alkyl-[NH—C₁-C₄alkylene]_(m),each of which is unsubstituted or substituted by one or more, whereapplicable identical or different, radicals R₁₇, or C₆-C₁₂arylunsubstituted or substituted by one or more, where applicable identicalor different, radicals R₁₈; R₁₅ is hydrogen, cyano, COO—R₂₅ orC₁-C₁₂alkyl; R₁₇ is halogen, hydroxy, O—R₂₅, cyano, COO—R₂₅ or carboxy;and R₁₈ is halogen, nitro, cyano, O—R₁₉, CH═C(CN)₂, COOR₁₉, ureido,CONR₂₅R₂₆, SO₂R₂₅, P(═O)OR₁₉OR₂₃ or unsubstituted or substitutedC₁-C₁₂alkyl.
 3. An optical recording medium according to claim 1,wherein the recording layer comprises a compound of formula (I) wherein


4. An optical recording medium according to claim 1, wherein thecompound of formula (I) contains branched C₃-C₂₄alkyl or branchedC₃-C₂₄alkenyl.
 5. An optical recording medium according to claim 1,wherein the recording layer is substantially amorphous.
 6. An opticalrecording medium according to claim 1, additionally comprising acovering layer, wherein substrate, reflector layer, recording layer andcovering layer are arranged in that order.
 7. An optical recordingmedium according to claim 1, which in addition to comprising a compoundof formula (I) comprises a metal-free chromophore.
 8. A method ofrecording or playing back data, wherein the data on an optical recordingmedium according to claim 1, are recorded or played back at a wavelengthof from 350 to 500 nm.
 9. A compound of formula (I) according to claim1, with the proviso that the compound is not a compound of formulaM₂(Z₁)₂, wherein:


10. A compound according to claim 9, containing branched C₃-C₂₄alkyl orbranched C₃-C₂₄alkenyl.
 11. A compound according to claim 9 of formula(I), wherein


12. An optical recording medium according to claim 1, wherein M₁ is Co,Cu, Ni, Pd or Zn.
 13. An optical recording medium according to claim 2,wherein the recording layer comprises a compound of formula (I) wherein


14. An optical recording medium according to claim 2, wherein thecompound of formula (I) contains branched C₃-C₂₄alkyl or branchedC₃-C₂₄alkenyl.
 15. An optical recording medium according to claim 2,which in addition to comprising a compound of formula (I) comprises ametal-free chromophore.
 16. An optical recording medium according toclaim 3, which in addition to comprising a compound of formula (I)comprises a metal-free chromophore.
 17. An optical recording mediumaccording to claim 4, which in addition to comprising a compound offormula (I) comprises a metal-free chromophore.
 18. A method ofrecording or playing back data, wherein the data on an optical recordingmedium according to claim 2, are recorded or played back at a wavelengthof from 350 to 500 nm.
 19. A method of recording or playing back data,wherein the data on an optical recording medium according to claim 7,are recorded or played back at a wavelength of from 350 to 500 nm.
 20. Acompound according to claim 10 of formula (I), wherein